(a) Field of the Invention
The present invention relates to the therapeutic or ameliorating effects of anthocyanin extracted from black soybean on varicocele or male infertility. In particular, the present invention relates to a method for treating or ameliorating varicocele or male infertility using anthocyanin extracted from black soybean.
(b) Description of the Related Art
Varicocele is the stretching and twisting of the pampiniform plexus of the spermatic cord through which venous blood flows in from the testis, and it is known to be the most common disease underlying male infertility. About 98% of varicocele occur on the left side, because the longer left testicular vein connects to the left renal vein with 90-degree angle, while the right testicular vein drains at less than 90-degrees directly into the significantly lager inferior vena cava. It is detected in approximately 15% of young males. In adults, it is asymptomatic in most cases; nonetheless, it has been reported to account for 35% of primary male infertility and 81% of secondary male infertility.
Until now, the treatments for male infertility caused by varicocele have included risky laparotomies or laparoscopic surgeries and procedures that occlude the expanded pampiniform plexus by angiogram. With the use of these techniques, improvements in the results of postsurgical semen analysis and an increase in the pregnancy rate have been reported. However, these surgical procedures could impose a heavy burden on the patients, and thus there is a need to develop effective drug therapy that can be more easily applied.
In this regard, studies of the mechanisms of abnormal spermatogenesis and infertility have suggested a reduction in gonadotropin or testosterone formation, increased scrotal temperature, apoptosis, reactive oxygen species, and ischemic changes caused by hypoxia as possible mechanisms inducing injury to the testis, but association of varicocele with male fertility has not yet been elucidated. Therefore, there are difficulties in developing effective drugs for varicocele or male infertility caused thereby.
Meanwhile, it is known that black soybeans contain essential fatty acids, lecithin, fiber, saponin or the like so that they have the effect of preventing and treating adult diseases such as hypertension, diabetes, arteriosclerosis, and obesity. The vegetable fiber contained in black soybeans is known to have the effect to prevent not only constipation but also colon cancer. Donguibogam describes black soybeans as “a drug that protects the five viscera, keeps intestines warm by helping twelve meridians, gets rid of boils, and treats radiating pain”.
Further, anthocyanin, a pigment contained in black soybeans, is a water-soluble pigment glucoside and known to have antioxidant, anti-aging and antibacterial effects. Anthocyanin is largely divided into six kinds of anthocyanidins depending on the number of the hydroxyl groups and the methylation of specific hydroxyl groups, and also divided into hundreds of kinds depending on the sort of sugar, which binds with anthocyanidins, and the sort and bonding location of the acyl group. It was recently found that each anthocyanin has slightly different bioactivities.
With regard to the medicinal use of anthocyanin extracted from black soybean, Korean Patent No. 10-0832240 provides the use of anthocyanin extracted from black soybean coat for the treatment of wound healing, and Korean Patent No. 10-0785466 provides the use of anthocyanin extracted from black soybean for the treatment of arteriosclerosis and heart diseases by suppressing NF-kB activation and myocardial necrosis after ischemia and reperfusion. In addition, Korean Patent No. 10-0880876 provides the use of anthocyanin extracted from black soybean coat for the treatment of skin flap or ischemia and reperfusion injury, and Korean Patent No. 10-2010-0127017 provides the use thereof for the treatment of diabetes. However, there are no reports about medical effects of anthocyanin extracted from black soybean on varicocele or male infertility in the prior publications including the above publications.
Accordingly, the present inventors have made many efforts to develop therapeutic agents effective for varicocele and male infertility caused thereby. As a result, they found that anthocyanin, extracted from black soybean seed coat, improves testis volume and spermatogenic cell density in a rat model of varicocele; prevents the apoptosis, leading to a reduction in the number of apoptotic bodies; and reduces oxidative stress, leading to a reduction in oxidative injury of DNA in testis tissues. Therefore, they demonstrated that anthocyanin, extracted from black soybean seed coat, is effective for making healthy sperm and furthermore useful for the treatment of varicocele and male infertility, thereby completing the present invention.